Reversing gears for diesel engines



March' I, 1942.

G.' E. RAMsTAD v REVIEIRSING` GEARS FOR DIESEL ENGINES Filed Aug. 1,1940 4 Sheets-Sheet l .Marh10,1942. l GERAMSTADL 2,2??921v REVERSINGGEARS FOR DIESELvENGNES Filed-Aug. 1, 1940" l' v4 Sheng-sheet 2 -IIII- 5Y n '"n" l um! f AHEAD um l NORMAL, LEAD v 44;

95 96 lol NORMAL SPEED attorneys March 1o, 1942. E, RAMS'TAD A'2,275,921

REvERsING GEARs FOR DIESEL. VENGINEs Filed'Aug. 1, 1940 sheets-sheet 3nun 3 March 1o, 1942.

G. E. RAMsTAD REVERSIG GEARS FOR DIESEL ENGINES FiledAug. 1', 1940 vsheets-snaai 4` AHEAD Cfttornegs Patented Mar. l0, 1942 Y nEvEaslNGGEAns Foa DIESEL ENGmEs George E. Ramstad, Milwaukee, Wis., assignor toNordberg Manufacturing Company, Mii

waukee,

Wis.. a corporation of Wisconsin Application August 1, 1940, Serial No.349,271

1,1 Claims. (Cl. 123-41) This invention relates to reversing gears forDiesel engines, and particularly to the reversal and control of fuelinjection in two cycle engines of the mechanical injection type.

In a pending application, Serial No. 258,777, filed February 27, 1939,issued June 3, 1941, as Patent Number 2,243,883 I describe a reversinggear for reversing not only the fuel pump mechanism, inlet and exhaustvalves of a four cycle Diesel engine, but also for reversing the airstarting mechanism. The whole mechanism is so interrelated, and isprovided with such interlocks, that a single controller is movable fromthe neutral or stop position in two opposite directions for reversedirections of operation. There is thus a forward range of motion and areverse range of motion of the controller. Each of these ranges issubdivided into three subranges. Counted in order from the stopposition, each first sub-range is one in which the reversing movementfor4 the various valve gears takes place, the second is an air startingrange in which the engine is put into motion by compressed air, and thethird is a fuel control range within which the starting air is cutoif'and the fuel feed is controlled, the feed increasing withdisplacement of the controller from neutral or stop position.

The present invention has to do with fuel injection only, and though thedevice is suited for use as the fuel injecting mechanism in the generalcontrol combination above defined, the novel features have to do solelywith fuel control, and, hence, will be discussed on that basis. Theinvention permits use of the gear of my prior application with two cyclemechanical injection engines.

I have determined that with a two cycle mechanical injection Dieselengine, the time of injection should be varied in relation to enginespeed, for very much the same reasons that the time of ignition isvaried in relation to engine speed in internal combustion enginesoperating on the Otto cycle.

The present invention produces a simple means for displacing the fuelcam shaft of a two cycle Diesel engine, angularly with respect to itsdrive,

so that a single set of fuel cams may be set alternatively for forwardand for reverse running.'

This primary adjustment is effected by means of a rack which engages agear associated with the cam shaft drive. A reversing motor moves thisrack full stroke between a vforward running position and a reverserunning position. In order to modify the lead or timing of the fuelinjection,

the parts are so formed that the gear is displaceable in the directionof its axis and transversely of the rack, and such displacement causesangular displacement of the cam shaft. In the preferred arrangement, therack is provided with teeth which are oblique with reference to therack, and the gear is mounted on straight splines so that it may beshifted transversely relatively to the rack. Such shifting, because ofthe lobliquity of the teeth, rotates the gearand hence .the shaft, inproportion to the lateral displacement .of the gear. Various alternativeschemes will suggest themselves.

Movement of the rack between forward and reverse position entailsmovement of a secondary member which is connected through a variablestroke linkage with the gear displacing means in such a way that themotion of the secondary member moves the aforesaid gear laterally, moreor less, depending on the'adjustment of the linkage. The adjustment ofthe linkage might be effected manually, but for best results it iseffected by a servo-motor under the control of a governor v responsiveto engine speed.4 It is not necessary or even desirable thatsuchservo-motor develop force suflicient to shift the linkage while thecams are 'actuating the fuel pump. By limiting the force developed bythe servo-motor, the adjustment may be caused to be intermittent,occurring when the cam shaft is lightly loaded. This reduces wear. Inthis discussion, the term lead is used to define the crank angle betweenthe start of injection and the dead point. l

Thus, the reversal of the engine is characterized by two concurrentadjustments ofthe angular position of the cam shaft relatively to thecrank shaft. The first or basic adjustment is of considerable range andestablishes the funda- Vthe desired variation of lead from normal speedto low speed is 4 in each position of running. From this it follows thatthe maximum angular rangeA of adjustment from minimum lead runningforward to minimum lead running reverse is 108. On this basis, theprimary adjustment could be'zset to give an angle of adjustment of 108,and the secondary adjustment could subtract from this 4 in each rangefrom mid-position, in which case the setting for maximum or normal leadwould involve a shift of only 100.

I prefer, however, and illustrate for purposes of disclosure, anarrangement in which the primary adjustment displaces the crank shaftthrough an angle of 100, and the lead varying adjustment lproduced byaxial displacement of the gear adds 4 for minimum lead conditions toeach direction of running, so that the extreme range of angularadjustment is108.

Because the two 'schemes are approximately equivalent and involve merelyreversals of pitch, it is deemed necessary to illustrate only thepreferred arrangement, in which the compensatory or lead adjustment isadditive rather than subtractive.

While the lead adjustment could be made manually, the invention givesits greatest utility when the lead adjustment is made in response toengine speed by a governor. An important aspect is that the control oflead by the governor is precisely the same for both directions ofrunning; i. e. the reversing gear introduces no disturbing factor as tothe governor control. The particular form of the governor is not afeature of the invention and will not be developed in detail. It isdesirable to use that type of govemor in which the speed responsivedevice pilots -a servo-motor and the motor develops the force necessaryto shift the lead controlling linkage.

Again referring to a commercial embodiment of the invention, it has beenfound satisfactory so to arrange the governor that it sets the mechanismfor normal lead at normal engine speed, and reduces the leadprogressively to the minimum value at an engine speed of approximately112 R. P. M. Below this speed, the minimum lead setting remains ineffect, because a change of lead below this speed has rio practicalsignificance.

The invention will now` be described with reference to the accompanyingdrawings, which are limited to the mechanism for changing the timing offuel injection, omitting all air starting gear but showing means forvarying the quantity of fuel injected. It should be understood, however,that mechanisms for accomplishing these purposes are well known and thatthe invention introduces no limitation on their use. In fact, it iscontemplated that the invention will be incorporated in a completereversing gear including mechanisms of the type mentioned.

In the drawings:

Figure 1 is a vertical section transverse to the crank shaft of amechanical injection Diesel engine, taken on the axis of one of thecylinders of the engine and through the fuel pump which delivers fuel tothat cylinder. The engine is shown set to run forward, and forwarddirections of motion of the various components are indicated by arrows.The reverse position of the cam for that cylinder is indicated in`dotted lines.

Fig. 2 is a vertical axial section through the reversing motor andrack,-with the lock mechanism, parts being shown in the up or forwardrunning position, and a portion of the rack being broken away to reducethe length of the figure. y

Fig. 3 is a horizontal section on the axis of the cam shaft, drawn on alarger scale than Fig. 1,

sition and with the secondary adjustment zero, so that there is maximumor normal lead.

Fig. 4 is a view similar to Fig. 3, showing ahead position with theminimum lead setting and showing. also, the planetary drive for the camshaft and the cam shaft with the cam in the ahead position of Fig. l.

Nora-With reference to Figs. 3 and 4, it should be observed that theright-hand end of each of these figures is toward the observer in Fig.1.

Fig. 5 is a detail view of the axially .shiftable gear. f

Fig. 6 is a detail view of the back of the reversing rack.

Fig. 'l is a section on the line 1-1 of Fig. 4. Fig. 8 is a section onthe line 0 8 of Fig. 4; and

Fig. 9 is a section on the line 9-9 of Fig. '7.

Referring first to Fig. l, |I represents the crank case and I2represents the jacketed cylinder of a Diesel engine. Only one cylinderis shown, but normally the engine would have a plurality of cylindersconnected to a common crank shaft with fuel injection pumps operated bycams on a single cam shaft, hereinafter described.

The piston I3 is connected byf the connecting rod Il to a correspondingcrank I5 on the main crank shaft I6. The cam shaft I1 turnsat crankshaft speed, as will hereinafter be described, and is provided with fuelcams I3, one for each cylinder. 'I'he forward setting of the cam shaftis indicated in full lines in Fig. 1, and the reverse position of thecam for the illustrated crank angle is indicated in dotted lines.

A roller cam follower I3 coacts with the cam to 'reciprocate the fuelplunger 2| of a variable feed fuel pump of the type known in the art asa Bosch fuel pump. The plunger 2| works in a cylinder 22 and may berotated about its longitudinal axis by a sleeve 23 which is splined tothe plungerv and which is rotated by the displacement offa rack 24. Theend of the plunger has a spill-back port indicated generally at 25, sothat the angular position to which the plunger is turned determines theamount of fuel delivered per stroke. The variable spill-back occurs atthe end of fuel delivery, so that the start of delivery is timed by thecam and the duration of delivery is controlledv by such angular positionof plunger 2|. The fuel oil is delivered through a check valve 28 andpipe 21 to a fuel injection nozzle 28 of known form. 'I'he presentinvention is concerned merely with the timing of reciprocation of theplunger 2|.

The crank shaft I6 carries a pinion 3| and this drives a large gear 32which is not fast on the shaft I1 but, on the contrary, is a ring gearon a cage 33 which rotates coaxially with the cam shaft I1. The cage 33is the housing of a planetary transmission which is coaxial not onlywith the cam shaft I1, but with an axially aligned timing.control shaft3l. The cage 33 carries a series of .beveled planet pinions 35 whichmesh with a beveled sun gear 38 fast on the control shaft 34 and with adriving gear 31 fast on the cam shaft I1. 'I'he ring gear 32 has twicethe pitch diameter of the crank shaft ,pinion 3| and,

consequently, the angular velocity of the cage 33 is half the angularvelocity of the crank shaft, but since the sun gear 36 is at rest,except for the reversing adjustments hereinafter described, the drivinggear 31 and the cam shaft I1 rotate and showing the reversing gear setin ahead po- A at twice the angular velocity of the cage 33.

pherlc port 51.

Consequently, the cam shaft turns at crank shaft speed, but in theopposite direction.

Remembering that reversal is to be effected by displacing the cam shaftI1 angularly with reference to the crank shaft I6, it will be apparentthat for any desired angular adjustment of the shaft |1, an equal andopposite angular adjustment of the shaft 34 must be made.

The shaft 34 having been related to the components of the engine whichare affected thereby, the discussion from now on will refer primarily tothe control shaft 34. lIt may be remarked that'no effort has beenmade-to illustrate the bearings which support the cam shaft l1 or thecrank shaft, because these features are conventional and do not enterinto the invention.

As in my prior application, above identified, reversal is produced byadmitting air to opposite ends of a pneumatic piston motor, the airsupply being cut oi and the motor vented as soon as it has completed itsworking stroke.

The air motor is shown in detail in Fig. 2. In this figure 4| representsthe air cylinder and 42 represents a motion controlling check cylinderthat is separated therefrom by an interposed cylinder head 43. A piston44 in the cylinder 4| is connected .by a rod 45 with a' check piston 45in the cylinder 42. The lower end of the rod 45 extends beyond thecylinder 42 and is connected to a rack 41. The two Working spaces in thecylinder 42 are connected by a pipe 48 with adjustable throttlingneedlevalve 49. The working spaces are kept charged with oil underpressure by a branch pipe which leads from a portion of the force feedlubricating system of the engine, a check valve52 being interposed. Thepiston 46, therefore, merely prevents unduly rapid reversing motion.

To move the piston 44 and, consequently, the rack 41 to forward setting,which is the one shown in Fig. 2, air is admitted to the lpipe 53 untilthe shift is completed and then -pipe 53 is vented. For reverseshifting, air is admitted to the pipe 54 until the shift is completed,and then the pipe 54 is Vented. The admission and venting functions arecontrolled by a maneuvering gear functionally similar to that formingthe subject matter of my prior application, and not hereinvolved.

Some means to latch the rack 41 in its two extreme positions arenecessary and are embodied in a latching motor enclosed in the housing55. Housing 55 takes the form of a diierential or shouldered cylinder inwhich works a combined latch piston and valve 56, also shouldered asshown. A coll compression spring 51 urges the piston to the right, sothat a latch nose 58 will engage beneath a latch shoulder 53 on the backof the rack 41 when the rack is in its upward or ahead position, andwill engage behind a companion shoulder 5| when the rack is in itsreverse position.

Leading from the housing 55 at the side opposite the connections 53 and54, and slightly offset axially therefrom, are two pipe connections. Thefirst, 63, leads to the lower end of the cylinder 4|, and the second,64, leads to the upper -end of the same cylinder. In the latchingposition of the piston 55, these connections communicate with exhaustports 55 and 55 in the. piston 56, so that `both working spaces incylinder 4| are then vented to atmosphere by way of atmos- When airunder pressure is admitted to the pipe 53, the piston 55 moves outwardso that the 75 exhaust ports 65 and 66 move out of register. At suchtime, the outward movement of the piston connects pipe-53 with pipe 63,and pipe 54 with pipe 54. Consequentlythe piston 44 is -moved upwardfull stroke, the space above the piston 44 being exhausted through thepipe 54.

When pressurefluid is admitted to the pipe 54, the reverse or downwardmotion takes place. At the end of thetraverse and-upon venting of thepipe 53 or 54, whichever was under pressure, the latch reengages. s

The apparatus shown in Fig. 2 is simplya full stroke vreversing motorwith a `uid pressure latch which engages to hold the rack at the limitof motion vafter `it has arrived at such limit. Various mechanisms ofthis type are known and equivalents may be substituted. In fact, anyfull stroke motor which will remain in its full stroke position at bothlimits of traverse could be used. The sole object is to move the rackfull stroke between two limiting positions and retain it in the nallimiting position. The upward position is the ahead setting-of thereversing gear, and the lower position is the reverse setting.

In Fig. 6. the back of the rack is illustrated. The latch shoulder 59 isshown. The cam slot 68 which coacts with a follower 69,'shown in Figs. A

3 and 4, is a part of the interlock of my prior application, whichassures that the reversing motor moves full stroke before the reversingair is cut olf. The cam slot 68 and follower 69 are not a part of thepresent invention and are here illu:- trated merely to indicate thepossibility of interconnection with the maneuvering mechanism of myprior application. No claim to such mechanism is made in the presentapplication.

The rack 41,1as best shown in Fig. 8, has Qblique teeth, and meshes witha spirally toothed gear 1| which is mounted on straight splines 10 onthe shaft 34. It is simpler to form the rack with inclined teeth and thegear 1| with spiral teeth than it would be .to make the splines 10spiral. Hence, the construction illustrated is adopted, but the basicidea underlying the mechanism is that axial displacement of thegear 1|across the face of the rack 41 shall entail limited terbored to receivean axially shiftable plunger 16 which is held in place by the screwplugs 11 which are threadedyinto the gear 1|v (see Fig. 9). Thecross-pin 16 is flat in cross section, as best kshown in Figs. 5, 8 and9, and the threaded counterbores for the plugs 11 occur in inactiveareas of the gear 1| fromwhich the teeth'are omitted. The maximum angleof motion of the gear'll is of the order of 108, so that the'omission ofa portion of the teeth at diametrically opposite points is practicable.

The counterbored portion voflongitudinally slotted as indicated at 18 toyafford clearance for the pin, but the torsional reaction the shaft y34is between the gear and the shait is taken up by the splines 10 and notby the pin 16. Similarly, as best shown in Fig. 7, the plunger 1.2 isarcuately slotted as indicated at 19, to permit free angular motion ofthe pin 18. Thus, the only duty imposed on the pin is to shift the gear1| in the direction of the axis of the shaft 34.

The outer end of the plunger 12 is slotted or bifurcated so that itaffords two parallel lugs or extensions 8|. These are each pinned onaligned axes 82 to one end of a corresponding one of a pair oflongitudinally channeled spaced links 88. The other ends of these linksare pinned on aligned axes 84 to a bifurcated yoke 85. The constructionis such that the two links 83 are parallel at all times, swinging inunison so that they are, in effect, a single link. However, for ease ofassembly, it is convenientto use two distinct links so connected thatthey move as one.

Each link has a longitudinal channel-like guideway 86 in which isslidable a fulcrum block 81. The two fulcrum blocks are pivoted onconcentric axes 88 to a slider 89 which is guided in ways 9| to move atright angles to the axis of the shaft 34. At the inner limit ofmotion,the pivots 88 are coaxial with the pivots 82, and under this condition,regardless of the position of the pivots 84, the gear 1| is in itsmid-position (see Fig. 3).

The slider 89 is connected by a link 92 with the controlling element f agovernor mechanism 93 which is responsive to engine speed. So

' far as is material to the present invention, the

governor mechanism is such that when the engine speed is normal, theparts assume the position shown in Fig. 3, in which the pivots 88 alignwith the pivots 82. As engine speed is reduced from normal, the slider89 is shifted progressive ly to the position shown in Fig. 4, which isthe low speed position. This position is assumed at a chosen minimumengine speed and all speeds below that minimum. In one engineconstructed according to the invention, this minimum speed was of theorder of 112 R. P. M. but the minimum is a matter of choice. Because theload on this governor is substantial, the governor should be of thatknown type in which the member 92 is shifted by a servo-motor inresponse to the indi.

cation of a. speed responsive device. Since such governors are wellknown in the art, detailed illustration is not necessary.

The yoke 85 is pivoted at 94 to some part which moves a definitedistance in a path parallel with the axis of shaft 34 during the fulltraverse of the rack 41. In the preferred embodiment, the pivot 94 iscarried by a threaded member which is traversed in a direction parallelwith the axis of the shaft 34 by a nut which rotates through adeniteangle as the result of the displacement of the rack 41 through its fulltraverse.

Thus, the threaded member is shown at 95 and is provided with multipleright hand quick pitch threads, 4as clearly shown atl96. 'I'he nut 91has companion internal threads 98 and is mounted to turn in bearings 99formed in a part of the housing mechanism. The nut is provided withspiral teeth |0| which mesh with the spiral teeth on the gear 1|, itbeing understood that the axis of the nut 91 is parallel with the axisof the shaft 34. It will require only a moments reflection to appreciatethat while the nut 91 is turned by the motion of the rack 41, it isunaffected by axial displacement of the gear -1|, for the pitch of thespiral threads is such that the gear 1| may be displaced axially whilethe nutl 91 and the rack 41 both remain at rest.

Operation v The operation of the device in motion from the .positionshown in the drawings, which is forward running position. to reverserunning position will now be traced.-

To bring about this action air is admitted to the pipe 54 until thepiston 44 moves downward its full traverse. The first effect is todisengage vthe latch i8 and upon venting of the pipe 54,

the latch reengages. It is unnecessary to discuss the action of theinterlock operated by the follower 69 and assuring full traverse beforethe air is cut off.

Assuming that the engine is at rest, the governor will position4 theslider 89 as shown in Fig. 4. As the rack 41 moves downward its fulltraverse, it will rotate the gear 1| and will also rotate the nut 91.The amount that the nut 91 rotates is directly proportional to thetraverse of the rack, but the amount that. the gear 1| rotates is thecombined eect of rotation by the rack and displacement of the gear 1|full stroke to the right as an incident to the displacement of thethreaded member 95 full stroke to the left. This reverses theinclination of the links 83 and .forces the plunger 12 inward relativelyto shaft 34. Consequently, the cam shaft |1 and cams |8 are displacedthe maximum angle, here assumed to be 108. When the engine operates andas its speed rises above 112 R. P. M., the governor moves slider 89progressively until pivots 88 and 82 align when normal speed isattained. By such motion, the gear 1| will be restored to itsmid-position (Fig. 3),.establishing normal lead conditions.

Reduced to its simplest terms, the transverse of the rack imparts adenite angular rotation to the gear 1|. At the same time it displacesthe pivot 84 a definite distance. The eect of the displacement of thepivot 84 is to reverse the inclination of the links 83. The governor 93effects the lead adjustment which must be in opposite senses foropposite directions of rotation, the desired reversal of sense beingproduced by the reversal of inclination of the links 83. The leadadjustment is effected solely by axial displacement of the gear 1|.

While the particular arrangement shown is simple to manufacture andprecise in operation, modifications within the broad scope of theinvention are possible, and are contemplated.

In the rst place, various modifications of the spiral arrangement bywhich axial displacement of vthe gear 1I causes rotation of the shaft 34while the rack remains at rest are obviously possible. The oneillustrated is selected because it is the simplest to manufacture.

It has also been suggested that the device can be arranged for asubtractive rather than for an additive effect of the lead adjustment.This would, for example, involve reversal of the slope ofthe teeth onrack 41 and gear 1| and appropriate change of the stroke of `rack 41 onthe diameter of gear 1|, to modify the extent of rotation of that gearimparted by the reversing cludlng a controlling member which whenrotated changes the angular relationship between the cam shaft and thecrank shaftto establish forward and reverse running conditions as to thetiming'of fuel injection', and also to modify the lead of suchinjection; a reversing member shiftable full stroke between a4 forwardrunning V position and a reverse running position; a driving connectionbetween said reversing member and saidcontrolling member through whichfull stroke motion of the reversing'member rotates the controllingmember suiciently to establish selectively said reverse runningconditions, said driving connections including a displaceablev componentso arranged that its displacement ro- -tates said controlling memberthrough a lead adjusting range; a reversible motion transmittingmechanism, connected with said reversing member so as to be reversed byfull stroke motion thereof, and connected with said displaceablecomponent to actuate the same; and a lead adjusting device connected toactuate said reversible motion transmitting mechanism, and

through it to actuate said displaceable compo- `nent in relativelyreverse senses in the forward the toothed actuator through a leadadjusting and reverse positions of said reversing member.

2. The combination defined in claim 1 in which the reversible motiontransmitting mechanism comprises a sliding block linkage including anoblique link and a sliding block serving as a fulcrum therefor, thereversing member being connected to reverse the Obliquity of the'linkand the lead adjusting device comprises a speed lilllesplcgansivegovernor arranged to shift the sliding oc l 3. The combination of anengine of the fuel injection type having a crank shaft, a cam shaftprovided with fuel injection cams, and

A fuel injecting means operated by said cams; a

drive train .from the crank -shaft to the cam shaft including acontrolling member which when rotated changes the angular relationshipVbetween the cam shaft and the crank shaft to ywhose displacement.changes the angular position of the controlling member relatively tothe position of the toothed actuator througha lead adjusting range;

a member moved by said range; a member moved by said toothed actuf atorto two distinct 'positions by the-shift of the actuator between its twolimiting positions; a reversible motion-transmitting mechanism arrangedto be reversely set by the shift of the last named member and connectedto movesaid axially displaceable components; shiftable lead controllingmeans arranged to actuate said axially displaceable component throughsaid motion transmitting mechanism, the imparted motionV being reversedby reversal of the motion transmitting mechanism; and a governorresponsive to engine speed for actuating said lead controlling means. n

5. The combination defined in claim 4 in which the governor is soarranged as to shift said lead controlling means progressively betweenfull engine speed and a low limiting speed, .and to maintain said leadconstant at a chosen minimum value at all speeds below said minimumspeed. 1

6. The combination of .an engine of the fuel injection type having acrank shaft, a cam shaft provided with fuel injection cams, and fuelinjecting means operated by said cams; a drive train from the crankshaft to the .cam shaft including a controlling member which whenrotated changes the angular relationship between the cam shaft and thecrank shaft to establish forward and reverse running conditions as tothe timing of fuel injection; a toothed actuator shiftable full strokebetween two limiting positions, one of which is'a forward andthe other areversev setting; a gear splined to saidcon- Y trolling member andhaving teeth engaging the shift of the actuator between its two`limiting positions; a reversible motion-transmitting mechanism arrangedto be reversely set by the shift of the last named member and connectedto move said axially displaceable component: and shiftable leadcontrolling means arranged to actuate said axially displaceablecomponent through said motion transmitting mechanism, the impartedmotion being reversed by reversal of the motion transmitting mechanism.

4. The combination of an engine of the fuel injection type having acrank shaft, a cam shaft provided with fuel injection cams, and fuelinjecting means operated by said cams; a drive train from Athecrankshaft to thecam shaft including a controlling member which whenrotated changes the angular relationship between the cam shaft and thecrank shaft to establish teeth of said toothed actuator', the forms oftheV teeth and of the spline being so correlated that vaxialdisplacement. of the gear in opposite directions from normal midpositionproduces rotary adjustment of the, controlling member through oppositelead adjusting ranges; a member moved by the shift of saidtoothedactuatorto two distinct positions; a reversible motion transmittingdevice reversely set by shift of the last named member and connected tomove said gear axially; and lead controlling means shiftable to` impartmotion to said motion transmitting device, the imparted motion beingreversed by reversal of the 'motion transmitting device.

'7. The combinationdened in claim 6 in which the toothed actuator hasoblique teeth and the splined gear which meshes therewith has spiralteeth.

8. The combination defined in claim 6 in which the member moved by theshift of the toothed actuator to two distinct positions is a second gearmeshing with said splined gear.

- 9. The combination of an engine of thefuel j injection type having acrank shaft, a cam shaft provided with fuel-injection cams, and fuelinjecting means operated by said cams; a drive of which is driven by thecrank shaft, and a third element of which is relatively fixed, butrotatable to change the angular relationship between the cam shaftandthe crank shaft, both to establish forward and reverse runningconditions as to the timing of fuel injection and to modify the lead offuel injection; a toothed actuator shiftable full stroke between twolimiting positions, one of which is a forward and the other a reversesetting; a gear splined to said third element of the planetary train andhaving teeth engaging` the teeth of said toothed actuator, the forms oi'the teeth and of the spline being so correlated that axial displacementof the gear in opposite directions produces lead modifying angularadjustment of the third element of the planetary train; a memberoperlatively connected with said toothed actuator to 10. The combinationdefined in claim 9 in,

which the reversible motion transmitting device comprises an obliquelink and a coacting sliding block, the member shifted by the toothedactuator serving in its two positions to establish relatively reverseoblique settings of the link, and the means for actuating the leadcontrolling means is connected to shift the block.

11. The combination of an engine of the fuel injection type having acrank shaft, a cam shaft provided with fuel injection cams and fuelinjecting means operated by said cams; a drive train from the cranksli-aft to the cam shaft including a controlling member which whenrotated changes the angular relationship between the cam shaft and thecrank shaft to establish forward and reverse running conditions as tothe timing of fuel injection, and also to modify the lead of suchinjection; a reversing motor shiftable full stroke between a forwardrunning position and a reverse running position; two individuallyoperable driving connections between said reversing motor and saidcontrolling member. one of said connections being a directconnectionthrough which the reversing motor turns said controllingmember through a range suilcient to effect reversal of timing relationand the other being a motion reversing connection comprising a shiftablefulcrum.member, a link fulcrumed thereon and connected to transmitmotion to said controlling member and means whereby the reversing motorreverses the Obliquity of the link relatively to the 4direction of shiftof the fulcrum member; and lead controlling means for shifting saidfulcrum member.

- GEORGE E. RAMSTAD.V

